Permanent Magnet Linear Motor Position Control Based On Adaptive Control

Permanent Magnet Synchronous Linear Motor(PMSLM)is a time-varying system object with obvious nonlinear characteristics.It’s more sensitive to disturbance and parameter variation.In addition,certain types of linear motors,such as iron cores,are subject to significant nonlinear effects due to periodic cogging forces and forces ripple.Generally used controller structures directly used in PMSLM with high frequency response characteristics unable to reach High-speed performance.A relatively mature self-adaptive control strategy is applied in the paper.Aiming at strongly nonlinear and time-variant characteristics of the PMSLM,on the foundation of identification of the system,the linear-motor position control is studied from both the Model Reference Adaptive Control(MRAC)and the self-tuning Control.Third-order point trajectory signal as the input,second-order adaptive controller has been forward and compared,which based on local parameter optimization MIT method(gradient)and global stability theory Lyapunov scheme.The results of simulation experiments indicate that the second-order controller based on Lyapunov second method is better than the controller in the other methods and respond rapidly and track perfectly the input third-order point trajectory signal,which confirmed the validity of position adaptive control on the PMLSM.Universal system identification software based of the principle of identification has created and mathematical model of PMLSM has built.According to the actual position input and output of linear motor,the parameters of linear motor are identified.In order to avoid un-modeled parts affecting on the accuracy,for instance current loop and velocity loop,PID closed-loop is added,which compared with the exact model identified by actual feed-forward iteration and the close-loop transfer function of linear motor position is obtained.A simplified mathematical model of PMLSM has been established by using dipole cancellation method,under guarantee original performance,that proved by comparing reduced order transfer function with before and shown in position output and bode diagram.Furthermore,a MRAC local parameter optimization MIT method and a Lyapunov method are used to design the position closed-loop controller.The stability of the adaptive control law and the controller parameter selection are discussed in detail.The controller gain coefficients and trajectory signal tracking response and complex controller structure was determined corresponding to more gain coefficients and controller initial values need to adjust are solved.Finally,the second order controller and satisfactory results achieved.Further the self-tuning control which combines the online identification with the controller design is elaborated in detail and the simulation experiments are carried out.At last,according to the position control algorithm of linear motor based on adaptive control is proposed in this paper,MATLAB software is used to carry out simulation experiment and system identification software off-line experiment.Analysis of local parameter optimization MIT method and a Lyapunov method are used to design the position closed-loop controller,which confirmed the validity of position adaptive control on the PMLSM and laid a foundation for the further research of linear motor position control.